Establishment of a Methods Development Core Laboratory within our Center is the most economical, efficient, and quality way to consolidate our development efforts. Validated assays of proven utility for testing normals and patients with infertility are critical to the ongoing support of the clinical and laboratory investigations whose goals are to precisely define the normative physiology in an area; to distinguish new pathophysiologic abnormalities; and to devise rational therapies. The strategic goals of this Methods Development Core are: a) to develop new reagents and assays useful to Center Investigators within their individual research Projects; b) to perform the biochemical and physiologic validation of these assays; and c) to transfer proven tests to high quality, high volume cores for performance. Thus, the Methods Development Core plays a critical role in the translational process between early investigative discoveries and the cost efficient performance of centralized clinical laboratory testing; in essence to facilitate bench to bedside transfer of U54 research progress. Given the Center's current focus on FSH regulation in the human, our current methods development will initially be brought to bear on providing 10 new assays for the clinical measurement of proteins comprising the inhibin/activin/follistatin system. Using a combination of whole molecule monoclonal antibodies already generated as well as sequence-specific antibodies directed at selected epitopes identified by structural analysis will be utilized to achieve specific double antibody 2-site assays for such closely related antigens. These assays will be designed and validated for measuring these proteins in serum, follicular fluid, and primary cell cultures. In close collaboration with Center investigators, the validity of these assays will be tested and normative databases established critical to the execution of the Specific Aims of the individual research projects. Subsequently, these assays will be made available to investigators of the collaborating Center within the Cooperative Research Program and to other NICHD-funded investigators.